i have tried just about everthing,swapped out carbs ,cdi , coil , this engine is new to me ,but the old one did the same thing that is why i am pretty sure it is electrical and i have ruled out stator problems since it is a completely different engine. it just misfires and runs like crap at lower rpms then goes away and runs pretty good.yes,both engines same symptoms . i am new to this website.any help would be greatly appreciated. could it possibly be the on/off switch or wiring harness ?this is all i can think of that has not been switched. i am getting very frustrated i have spent hours reading other posts on here to get ideas .thanks